The present invention relates to a method and apparatus for defrosting a heat exchanger coil of a transcritical vapor compression system.
Transcritical vapor compression systems typically include a compressor, a gas cooler, an expansion valve and an evaporator. Typically, electric heaters are installed in front of a heat transfer surface of the evaporator for defrosting the evaporator heat transfer surface. When a defrost mode is initiated, a controller stops the compressor and energizes the electric heaters. The heaters are turned off, and cooling mode resumes, when the evaporator coil temperature increases.